block: remove the write_hint field from struct request

[ Upstream commit 61952bb7 ]

The write_hint is only used for read/write requests, which must have a
bio attached to them.  Just use the bio field instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20241112170050.1612998-2-hch@lst.de


Signed-off-by: Jens Axboe <axboe@kernel.dk>
Stable-dep-of: fc0e982b ("block: make sure ->nr_integrity_segments is cloned in blk_rq_prep_clone")
Signed-off-by: Sasha Levin <sashal@kernel.org>